Improved machine foe grinding and polishing school-slates



@uiten tat getint @ffice STINSON HAGAMAN, OF WEISSPORT, PENNSYLVANIA.

Letters Patent No. 82,828, dated October 6, 1868.

IMPROVED MACHINE FOR GRINDING AND POLISHING SCHOOL-SLATES,

tlgrrlgtuh referat tu in tigen ttert rttnt emanating mi tt tigt ma.

TO ALL WHOM IT MAY GONCERN: y

Be it known that-I, STINSON HAGAMAN, vof Weissport, in the county of Carbon, and State of Pennsylvania, have in vented a new `and useful Improvement in Machines for Grinding and Polishing School-Slates; and I do hereby declare that the following is a full, clear, and exact description thereof, reference beinghad to the accompanying drawings, and to the letters of reference marked thereon, iu whch- Figure 1 is a side elevation of the machine.

Figure 2 is a plan view of same'.

Figure 3 is a side elevation of one ofthe slate-carriers, detached; and

Figure 4 is a cross-sectionlot` one of the top rails of the frame and carrier, in line a: x, lig. 2.

Like letters indicate the same parts in all the iigures.

A is the main frame of the machine. v l v B and Bl are two rubbing-wheels, of diiferent grades of grit,.the first, or B', to grind down the slate, and the next, B, to polish it. e

C and C are two pulley-wheels, carrying an endless belt, D, and on this endless belt are to be mounted as;

many slate-holders or carriers, H, as may be desired. l

The crank-shaft Gr is the shaft, to which any suitable motive-power is to be applied, to give it aaotary motion. 1

` On the lower end of this shaft is a large pulley-wheel, E, and in the same plane, on the lower ends of thel vertical shafts on' whichthe rubbing-wheels B and Bl are mounted, are `two smaller pulley-wheels, F and F. An

endless belt, E, passes around all three of these pullcywheels,and so gives motion to the rubbing-wheels B B.

I is a pinion-wheel, mounted on the same shaft with the pulley-wheel C, and meshes into a worm-screw, J, on the crank-shaft G, and by this means said pulley-wheel C is so rotated as to'carry the endless belt D, with its slate-carriers H, at the proper rate ofv speed to move said carriers successively under the rubbing-wheels,

and subject each slate a suiiicient lengt-h of time to the action of said wheelsthereon.

The slate-carriers or holders are each moun'ted on four friction-rollers, 1', by means of'two springs, s. These friction-rollers run upon ledges or tracks, Z, upon the upper rails of the mainframe. The springs s hold the slates up against the rubbing-wheels with suiiicient force' to cause them to be properly ground and polished, but at the same timelallow the slate-bed to yield suilicently to accommodate the machine to slates of different thicknesses, and prevent breakage thereof. 'I

The slate-beds L, while passing under 'the rubbing-wheels, are guided by shoulders, tt, on the upper rails ofthe frame, so that they cannot be depressed below a defined line, or pass'through the machine without being reduced to a limited and definite thickness.

The upper rails ofthe frame, or the ledges thereon which guide the carriages, should be slightly depressed at the narrow end of the machine, to allow the slates to pass freely under the first rubbing-wheel, and cause I them afterwards to rise up and press against it.

The slates are to be fastened to their beds on the carriages by a slide and thumb-screw, or by any other suitable known means for performing similar operations.

The tender stands at the narrow end ofthe machine, and fastens a slate on each carriage as it passes.

I design using a canvas endless belt to run underneath and parallel with the carriages, to catch any slates I that may happen to fall from them while they are inverted, and carry them back t0 the tender. Each slate' may be permitted to pass as many timesA under therubbing-wheels as may benecessary to finish it, when it will be removed by the tender and replaced by another. The carriages willmove slowly enough to permit'this being done while the machine is in motion.

The rubbing-wheels are to be made adjustable in vrespect to their height abovethe frame, which may be done by obvious means, not necessary to here describe. Said rubbing-wheels may be made of wood, and coated' with emery, or any other suitable gritty material, or thewheels themselves may4 be mode of any other suitable material besides wood.

Having thus fully described my machine, and .its mode of operation, whetI claim as my invention, and

desire to secure by Letters Patent, is

1. In combination with one or more horizontally-rotating rubbing-wheels, an endless belt, .with slatecarriages mounted thereon, for the purpose of carrying the slates under the rubbing-wheel or wheels, substantially as described. 4 2. In combination with one or more rubbing-wheels, as described, and an endless b elt, for the purpose of carxying the slates, as set forth, I claim the slate-carriages H, with their friction-Wheels and springs, as described.

3. In combination with the endless belt, :md slate-carriages mounted thereon, as described, I claim the ledges or tracks nZ and shoulders t, on the rails of the machine, for the purposes set forth.

4. I claim the combination of the driving-shaft G, the pulley/wheels E, F, and F', with the endless belt E', for rotating the rubbing-wheels, and the pinion I, worm-screw J, und pulley-Wheels C und C', for carrying the endless belt D, ell arranged and operating substantially as described.

STINSON HAGAMAN.

Witnesses:

A. S. CHRISTINE, LEWIS W. GREENZWEIG. 

